This investigation was supported by Grants NS 06853 from the National Institute of Neurological Diseases and Stroke and 430-13 RD from the Illinois Department of Mental Health. J.V.H. is a predoctoral trainee (5 TO1 GM-00724) from the National Institute of Gcneral Medical Sciences. The authors wish to thank Dr. A. VEIS and Ms. RUTH FULLERTON for the amino acid analyses and their helpful advice.
THE EFFECTS OF PHENYLALANINE ON AMINO ACID METABOLISM AND PROTEIN SYNTHESIS IN BRAIN CELLS IN VITRO1
Article first published online: 4 OCT 2006
Journal of Neurochemistry
Volume 26, Issue 6, pages 1105–1113, June 1976
How to Cite
Hughes, J. V. and Johnson, T. C. (1976), THE EFFECTS OF PHENYLALANINE ON AMINO ACID METABOLISM AND PROTEIN SYNTHESIS IN BRAIN CELLS IN VITRO. Journal of Neurochemistry, 26: 1105–1113. doi: 10.1111/j.1471-4159.1976.tb06993.x
- Issue published online: 4 OCT 2006
- Article first published online: 4 OCT 2006
- (Received 23 May 1975. Accepted 24 November 1975)
Incubation of brain cell suspensions with 14 mM-phenylalanine resulted in rapid alterations of amino acid metabolism and protein synthesis. Both thc rate of uptake and the final intracellular concentration of several radioactively-labelled amino acids were decreased by high concentrations oi phenylalanine. By prelabelling cells with radioactive amino acids, phenylalanine was also shown to effect a rapid loss of the labelled amino acids from brain cells. Amino acid analysis after the incubation of the cells with phenylalanine indicated that several amino acids were decreased in their intracellular concentrations with effects similar to those measured with radioisotopic experiments (large neutral > small and large basic > small neutral > acidic amino acids). Although amino acid uptake and efflux were altered by the presence of 14 mwphenylalanine, little or no alteration was detected in the resulting specific activity of the intracellular amino acids. High levels of phenylalanine did not significantly altcr cellular catabolism of either alanine, lysine, leucine or isoleucine. As determined by the isolation of labcllcd aminoacyl-tRNA from cells incubated with and without phenylalanine, there was little or no alteration in the level of this precursor for radioactive alanine and lysine. There was, however, a detectable decrease in thc labelling of aminoacyl-tRNA for leucine and isoleucine. Only aftcr correcting for the changes of the specific activity of the precursors and thcir availability to translational events, could the effects of phenylalanine on protein synthesis be established. An inhibition of the incorporation into protein for each amino acid was approximately 20%.